1. Technical Field
The present invention pertains to a cast iron material. The present invention specifically pertains to a ledeburitic cast iron material with free, evenly distributed graphite formation and a high carbide content of at least 15 wt. % which can be used for the manufacture of sliding rings for use in running gear seals or cylinder liners of engines.
2. Related Art
State of the Art
Running gear seals that run with high peripheral speeds (>5 m/s) are required more and more frequently in technical applications. The materials used nowadays such as, for example, Ni-Hard cannot fulfill the corresponding requirements with respect to high peripheral speeds at larger dimensions (D>600 mm). The frictional heat generated on the contact surfaces of the sliding rings cannot be carried off sufficiently fast due to the insufficient thermal conductivity of the material and scoring occurs. This destroys the sealing surfaces and results in impermissible leakage.
According to the state of the art, hardened high-alloy and unalloyed steel, as well as stellites, cast nickel, various white cast iron and cast iron materials such as, for example, Ni-Hard and gray cast iron are used in the manufacture of running gear seals.
In special applications in which the diameter (D) of the seal exceeds 600 mm, steel materials are not used for reasons of manufacturing and application technology because, among other things, the maximum attainable peripheral speed lies below 4 m/s in this case.
In the special field of applications in which the diameter (D) of the seal exceeds 600 mm, for example, a white cast iron material such as Ni-Hard 1 is used, but the peripheral speed of this material is limited to 5 m/s.
Another material such as, for example, siculite (gray cast iron) has inferior wear and corrosion characteristics in comparison with (Ni-Hard 1) and therefore is used rather rarely, particularly for the cited reasons.
The problem of optimal wear and corrosion resistances, thermal conductivity and absence of leakages in connection with high peripheral speeds (>5 m/s) of ring seals in the diameter range (D>600 mm) has not been solved so far for the application in axial face seals and/or cylinder liners.